In materials processes, for example making a cut in wood or a similar material, it is important to be able to precisely control the relative movement of the workpiece and the saw blade to ensure that the resulting cut is formed with the desired dimensions. However, precisely controlling the relative movement of the workpiece and the saw blade can be challenging when making, for example, irregularly shaped, curved, and angled cuts. Thus, guiding surfaces have been developed which can be firmly yet movably attached to cutting devices to provide a stable surface to guide the relative movement of the workpiece and the saw blade during the cutting process.
In particular, miter gauges have been developed to guide workpieces when angled cuts are made with a table saw. As shown in FIG. 1, a table saw 10 includes a saw blade 12 and a table top 14 having a slot 18 formed in a work surface 20 and the table top 14. The table saw 10 also includes a miter gauge 22, which includes a miter attachment 26 and a miter bar 30. The miter bar 30 is slidingly received in the slot 18 to slidably couple the miter gauge 22 to the table top 14. When the table saw 10 is used to perform a cutting operation that does not require the miter gauge 22, the miter gauge 22 can be removed from the table top 14 by sliding the miter bar 30 completely out of the slot 18. The miter attachment 26 is rotatably coupled to the miter bar 30 and has a planar miter surface 34, which provides a stable guiding surface to the workpiece. The miter surface 34 is not visible in FIG. 1, but its location is indicated by an arrow. Thus, because the miter bar 30 is rotationally fixed relative to the work surface 20 by the slot 18, rotationally adjusting the miter attachment 26 on the miter bar 30 sets an angle of the miter surface 34, and thus of the workpiece supported by the miter surface 34, relative to the saw blade 12.
As shown in FIG. 2, the slot 18 formed in the work surface 20 and the table top 14 has a “t” shape, including a main opening 38 and an engagement opening 42. The main opening 38 includes a first wall 46 and a second wall 50, which are formed opposite and facing toward one another. The first and second walls 46, 50 are spaced apart from one another by a first distance D1. The first and second walls 46, 50 are formed perpendicularly to the work surface 20, such that, as shown in FIG. 2, they are vertical. The engagement opening 42 is formed within the main opening 38 and includes a third wall 54 and a fourth wall 58, which are opposite and facing toward one another. The third and fourth walls 54, 58 are parallel to the first and second walls 46, 50 such that the third and fourth walls 54, 58 are also vertical. The third and fourth walls 54, 58 are spaced apart from one another by a second distance D2, which is larger than the first distance D1. Thus, the engagement opening 42 is formed as a wider cut-out in the main opening 38. The slot 18 further includes a fifth wall 62, which is formed between the first wall 46 and the third wall 54, and a sixth wall 66, which is formed between the second wall 50 and the fourth wall 58. The fifth and sixth walls 62, 66 are perpendicular to the first, second, third, and fourth walls 46, 50, 54, 58 such that the fifth and sixth walls 62, 66 are horizontal.
As shown in FIG. 3, the miter bar 30 is generally matingly shaped to slide within the slot 18. The miter bar 30 includes a main portion 70, configured to slide between the first and second walls 46, 50, and an engagement portion 74, configured to slide between the third and fourth walls 54, 58. Accordingly, the main portion 70 has a first width W1, which is smaller than the distance D1 (shown in FIG. 2), and the engagement portion 74 has a second width W2, which is larger than the first distance D1 and smaller than the second distance D2 (shown in FIG. 2). Thus, the engagement portion 74 of the miter bar 30 engages within the engagement opening 42 of the slot 18 and prevents the miter bar 30 from being lifted out of the slot 18 in a direction perpendicular to the work surface 20.
Often, miter gauges 22 are a separate accessory to the table saw 10 and are configured to be repeatedly insertable and removable, as needed, from the table saw 10. Accordingly, the relative dimensions of the miter bar 30 and the slot 18 must be sized so as to allow the miter gauge to slide smoothly. Furthermore, the slots 18 formed in different table saws 10 may not have the same first and second distances D1, D2. Accordingly, the main portion 70 and the engagement portion 74 must be sized so as to fit within slots 18 having some dimensional variation. Finally, each of the slot 18 and the miter bar 30 will be produced having dimensions within manufacturing tolerances. Accordingly, each slot 18 and each miter bar 30 will have unique dimensions, and the slot 18 and the miter bar 30 must be sized to accommodate the manufacturing tolerances of the matingly formed part.
As shown in FIG. 3, due to the aforementioned size requirements and variations of the slot 18 and miter bar 30, gaps 78 may be present between the main portion 70 of the miter bar 30 and the main opening 38 of the slot 18. These gaps 78 prevent the miter bar 30 from resting firmly against the first and second walls 46, 50 of the slot 18. Thus, when pressure is applied on a workpiece guided by the miter surface 34, the pressure is transferred through the miter attachment 26 and into the miter bar 30, and the miter bar 30 is moved within the slot 18 until the main portion 70 contacts one of the first and second walls 46, 50 of the slot 18. This movement of the miter bar 30 prevents cuts from being precisely formed in the workpiece, because it prevents the position of the miter gauge 22, and thus the position of the workpiece, from being precisely controlled relative to the saw blade 12.
In view of the foregoing, it is apparent that there is a need for an adjustable miter gauge for table saws, which can prevent unwanted movement of the miter bar within the slot. There is also a need for an adjustable miter gauge for table saws, which can be adjusted to the dimensions of various slots. There is also a need for an adjustable miter gauge for table saws which enables easy adjustment of the width of the miter bar.